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U.S. drone strikes against al Qaeda suspects are on the upswing in Yemen

Three suspected al Qaeda militants were killed by a U.S. drone strike in Yemen's southern province of Lahj, two local security officials told CNN on Saturday.

Two others were injured in the Askariayah district strike, one of whom was critically injured, the officials said.

A second vehicle in the same area carrying suspected militants escaped undamaged after a strike missed its target.

Residents told CNN that the drone had been flying in low altitude between the two strategic districts of Yafe'e and Radman since the early afternoon.

"The militants were taking a weapons shipment by vehicle to a different location when that strike took place," a local security official told CNN on condition of anonymity because he is not authorized to talk due to the sensitivity of the issue.

The official said two of the killed were not from Lahj province and that very few strikes occurred in Lahj province over the last two years.

"Pro-government fighters have made it difficult for al Qaeda militants to move around in the province after their defeat last year," he added. The strike was the tenth since President Abdurabu Hadi ended his visit to the United States earlier this month.

A senior Defense Ministry official told CNN that 34 people have been killed in 12 drone strikes since July 28. The official said that nearly a dozen of the killed over the past two weeks are believed to have been innocent.

Four Western embassies have been closed since August 4, after US intelligence intercepted information that al Qaeda would target American interests in the region.

Drone strikes against militants in Yemen have been intensifying as the U.S. Embassy there and in other Middle Eastern and African countries have been closed amid terrorism fears.

Security presence has decreased over the past two days in the Yemeni capital, Sanaa, after hundreds of additional troops were deployed after the terror alert on August 3.